> For the complete documentation index, see [llms.txt](https://gsm.learn-telecom.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gsm.learn-telecom.com/standards/timeline.md). # Timeline ## 1988 ### GSM 900 Uplink - 890 Mhz to 915 Mhz Downlink - 935 Mhz to 960 Mhz ### GSM 1800 1710 Mhz to 1785 Mhz 1805 Mhz to 1880 Mhz ## 1995 ### GSM 1900 1850 Mhz to 1910 Mhz 1930 Mhz to 1990 Mhz ## 1996 120 GSM Networks ## 2000 150 million GSM users GSM (Global System for Mobile Communications) is a standard developed to describe protocols for second-generation (2G) digital cellular networks. By 1996, there were 120 GSM networks operating globally. By 2000, the number of GSM users had grown to 150 million, showcasing its rapid adoption and widespread usage. The frequency band 1930 MHz to 1990 MHz is commonly used for mobile communication services, including GSM, in various regions. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://gsm.learn-telecom.com/standards/timeline.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.